If you follow me on Twitter, you would know that I am heavily into my weather stuff and that I have running every six hours a few scripts that I have mashed together to generate visible weather maps for the temperature, wind speed, rain and pressure for the British Isles. Now when these maps have generated, they can be quite hefty. The last weigh-in I did for the maps was 73.2MB, which if you're wanting to quickly browse them and you're not on a 4G or decent WiFi connection end up loading quite slowly.

I did however come across a brilliant free tool that compresses PNG files even further without losing ANY visible quality. I had to try it myself to believe it and I was shocked. I got the weather maps folder of 73.2MB down to 21.2MB! That's over 50MB that's been reduced! And for that reason, I'm giving pngquant a brilliant shout out!

Just to demonstrate how well it works, here's one of the images from my weather section:

Original

And then I have ran pngquant on it, using

pngquant --force --quality=45-85 --ext .png

pngquant

Can you notice a difference at all in the pictures? No? Neither did I, but what I did notice was the file size. The original PNG came in at 265KB, the pngquant PNG came in at 77.5KB. A reduction of 187.5KB.